New cardiovascular technologies are often embedded in a context of uncertainty and controversy. Given the rapid escalation in costs, the assessment of these technologies for safety and efficacy has taken on added importance. Medical technology assessment typically involves the synthesis of results from multiple research studies. The proposed research seeks to refine further a fundamental part of the assessment process, the synthesis of outcome data from controlled trials. Five syntheses would be conducted on a variety of important medical technologies of both a mature and an emerging nature. The data synthesis approach offers the important advantage of maximizing the information value of previous research at minimal expense. A secondary purpose of the proposed research is to develop a system for quickly and inexpensively archiving and analyzing relevant data from controlled trials and to reduce the usual expense associated with these activities. The data archive and analytic procedures will be stored on a microcomputer system. This will permit the archive to be used by other researchers and clinicians for secondary analysis or to conduct other syntheses of interest to them. The data synthesis approach allows various temporal factors such as the changing nature of the cardiovascular technology, the type of comparison group, and the mix of patients to be monitored and assessed. It is our view that a synthesis system that monitors the relative advantage or disadvantage of a particular technology is valuable for "state of science" activities such as consensus development conferences and for targeting expensive clinical trials or other, smaller funding initiatives. A pilot evaluation study would be conducted to assess the capacity of the system to conduct policy-relevant, timely syntheses. The specific technology will be chosen by NHLBI's Office of Program Planning and Evaluation. Continuous data monitoring also allows the archive to be updated as the results of new clinical trials of a particular cardiovascular technology are published. In addition, findings from emerging technologies can be added to the data archive earlier in the dissemination process so that informed assessment of beneficial, no-difference or harmful outcomes can be made with minimal delay. These would include: hypertension treatments, percutaneous transluminal coronary angioplasty, calcium blockers, coronary care units, and other cardiovascular technology to be selected later.